1. Field of the Invention
The present invention relates to he field of assembly of metal sheet piles, in particular of steel, for forming, for example, walls which must provide a good tightness with respect to liquids, such as water.
2. Description of the Prior Art
It is known that the edge portions of the sheet piles are so shaped as to permit the hooking of one sheet pile to another in a connection which may provide a more or less large degree of flexibility. Different types of shape for the edge portions of sheet piles exist, these edge portions being termed "claws". Some types of claws, in particular those of the sheet piles termed "Larssen" sheet piles, have a planar bearing surface and, upon the assembly (termed "interlocking") of two sheet piles, achieved by sliding one claw in the other, the planar bearing surfaces of their respective claws come to face each other. Other types of claws have only curved surfaces.
It may be desired to render the connections between two sheet piles tight or sealed, in particular in the case where they are intended to be part of a wall partly immersed in an aquatic medium, for example in a harbor construction. Several sealing methods are essentially employed. First, the sheet piles may be welded after their assembly. This method takes a long time to carry out and the weld must be made before the immersion of the assembly. Further, the connection sealed in this way remains perfectly rigid, whereas a certain flexibility may be desired. A second method consists in, after the interlocking of the sheet piles, injecting into the space left free between the claws a material, for example based on polyurethane, which is in the liquid state and subsequently hardens and forms an elastic sealing element (see the German patent No. 2722978). This method presupposes that, at the moment of the injection, the sheet piles have already taken up their final positions and that one of the ends of their connection remains accessible. A third method consists in depositing on the claw of one of the sheet piles of the assembly a layer of an organic material which has a certain elasticity, such as a polyurethane or a rubber, and which may also have the feature of swelling in the presence of water. Such a material is described for example in the European patent No. 50906. The connection is correctly sealed and it retains a certain flexibility. However, the layer of organic material is often torn away or damaged when interlocking the sheet piles, by the effect of intense frictions which occur between the layer and the claw of the other sheet pile. The elastic organic material is consequently no longer able to perform its function in an effective manner.